MiniPlex-2S NMEA-0183 multiplexer
Manual
MiniPlex-2S, V1.0
Firmware V2.10
Art.no.: 1120
Man. rev. B
© CustomWare, 2010
Introduction
The MiniPlex-2S is a four-channel NMEA multiplexer, enabling the connection of multiple NMEA0183 instruments to each other and a computer. Available are four NMEA inputs (listener-ports),
two NMEA outputs (talker-ports) and one serial port (RS-232) for connection with a computer. The
multiplexer offers many features for manipulating incoming NMEA data like sentence filtering, real
time mode, talker ID modification and SeaTalk to NMEA translation in order to read data from
Raymarine instruments like the ST40, ST50 and ST60 series.
Operation
The multiplexer receives NMEA sentences on the listener ports and forwards them to one or more
talker ports and the serial port with equal priority. When NMEA sentences are received
simultaneously, they are stored and transmitted sequentially. This basic function allows data of
several instruments to be combined into one integral stream of data, to be sent to other navigation
equipment and/or a computer. One input of the multiplexer (In 4) can be set to SeaTalk mode. The
multiplexer will then translate SeaTalk® data from a Raymarine® network into NMEA sentences.
Wind
In 1
Laptop
RS-232
Compass
In 2
GPS
In 3
Out 1
Multiplexer
Auto-pilot
The picture above shows a typical configuration where data from a wind instrument, a compass
and a GPS are combined and forwarded to a laptop. Data that is returned from the laptop to the
multiplexer is sent to an autopilot.
The operating mode of the multiplexer determines which information goes where. In Server mode,
the data from wind, compass and GPS are only sent to the laptop. The autopilot on Out 1 only
receives route and track data from the laptop. In Hub mode however, the multiplexer combines
the data from wind, compass and GPS with the data received from the laptop and sends it to the
autopilot on Out 1. This way the autopilot also has access to the wind, compass and GPS data. See
‘Mode of operation’ for more details.
Overflow
Depending on the configuration of the multiplexer, NMEA sentences are sent to one or more talker
ports with different communication speeds. A situation could arise where more data is received
than can be transmitted because of certain speed settings on some of the listener or talker ports.
Such a situation leads to an overflow of data in some of the internal buffers of the multiplexer.
When an NMEA sentence is being received while a buffer is full, this sentence is discarded
completely to ensure only complete NMEA sentences are stored and forwarded. This event is
indicated by the red LED, which will blink briefly when a sentence is discarded.
A couple of occasional blinks of the red LED each second means that some sentences are discarded
but most of them will be passed without problems. Such a situation is totally acceptable and would
practically mean that for instance one depth, wind or position update is missed.
When the red LED is blinking severely or stays on almost continuously, it is advisable to investigate
which instrument leads to this overflow. The MPX-Config utility will show on which input the
overflow occurs. One typical situation could be where a fluxgate compass sending 10 heading
sentences per second or more is continuously filling up the buffer. This leads to a situation where
the heading information output by the multiplexer is 20 seconds old. Such a situation could be
resolved by either using the Sentence Filter to reduce the frequency of the fluxgate’s NMEA
sentences or to enable Real Time mode for the input the fluxgate is connected to.
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Some general rules are applicable for reducing overflow situations. A simple rule of thumb is that
an overflow can never occur if the speed of an output is equal or higher than the combined speeds
of all applicable inputs. For example: if the multiplexer is in Server mode and all four inputs are
set to 4800 baud, the minimum output speed equals 4 x 4800 = 19200 baud. This rule is only a
hard rule when the input bandwidth is fully utilized i.e. an instrument is sending data continuously.
This is never the case. Generally an instrument only sends one or more sentences per second,
resulting in a much lower bandwidth. It could be perfectly feasible to have an installation where
four instruments are connected to the multiplexer, while running all in- and outputs on 4800 baud
without a single overflow.
There are several ways to resolve overflow situations:
1.
Configure the instruments on the listener ports to send less data or with greater intervals.
It is often possible to disable non-relevant sentences.
2.
Many instruments do not allow selection of NMEA sentences to be output. In this case, use
the NMEA sentence filter of the multiplexer to block unwanted sentences. Unwanted
sentences are discarded immediately and do not occupy buffer space or bandwidth.
3.
Set the operation mode of the multiplexer to Server mode (factory default). This mode
only sends incoming data to the computer and to NMEA Out 2, which is factory set to high
speed (38400 baud). In Hub mode, the high-speed ports must wait for every character to
be transmitted over any low speed ports.
4.
Increase the speed of the Out 2 port on the multiplexer, especially when this port is not
used. The maximum speed is 38400 baud. From 19200 baud and up (4 x 4800!) an
overflow will never occur, except when the multiplexer is set to Hub Mode.
The multiplexer has two talker ports, NMEA Out 1 and NMEA Out 2. All received sentences from
the listener ports are available on talker port NMEA Out 2. Talker port NMEA Out 1 can be
configured to output either all received sentences from the listener ports and the serial port (Hub
mode), or sentences from the serial port only (Server mode). See the table below.
NMEA Out 1
NMEA
In 1
H
NMEA
In 2
H
NMEA
In 3
H
NMEA
In 4
H
Serial
In
H/S
NMEA Out 2
H/S
H/S
H/S
H/S
-
Serial Out
H/S
H/S
H/S
H/S
-
H: Hub mode, S: Server mode
3
Connections
NMEA Listener Ports
The multiplexer has four listener ports, In 1 to In 4. Each listener port should be connected to one
instrument only. These inputs are galvanically isolated from the multiplexer, as specified in the
NMEA-0183 standard.
Connect the a and b terminals of the listener port on the multiplexer to the a and b terminals of
the talker port on the instrument. Other designations used are for instance Data+ and Data-, TX+
and TX- , Out+ and Out– or ve+ and ve-.
Some instruments have single ended talker ports, with only one data terminal. Connect this
terminal to the a terminal on the multiplexer, and connect the ground of the instrument to the b
terminal on the multiplexer. The instrument’s data ground is often combined with its power supply
ground.
Out A / +
In A
TX
In A
Out B / -
In B
GND
In B
Instrument
Multiplexer
Instrument
Differential
Multiplexer
Single-ended
NMEA Talker Ports
Both talker ports can be connected to up to four instruments. Connect the a and b terminals of the
talker port on the multiplexer to the a and b terminals of the listener port(s) on the instrument(s).
Other designations used are for instance Data+ and Data-, TX+ and TX- , Out+ and Out– or
ve+ and ve-.
Some instruments have single ended listener ports, with only one data terminal. Connect this
terminal to the ‘a’ terminal on the multiplexer, and leave the ‘b’ terminal on the multiplexer
unconnected. Connect the ground of the instrument to the Com terminal on the multiplexer. The
instrument’s data ground is often combined with its power supply ground.
Out A
In A / +
Out A
RX
Out B
In B / -
Out B
GND
Com
GND
Multiplexer
Instrument
Multiplexer
Differential
Instrument
Single-ended
Out A
In A / +
In A / +
RX
Out B
In B / -
In B / -
GND
Com
Multiplexer
Instrument
Instrument
Multiple instruments
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Instrument
The shield terminals (Shld) can be connected to the screen/shield of the cable if present. This
should always be done on one end of the cable only, preferable on the talker side.
SeaTalk
SeaTalk® is a proprietary protocol developed by Raymarine®. This protocol is used for
communication between Raymarine navigation instruments like the ST40, ST50 and ST60 series.
To be able to use these instruments with commonly available navigation programs or to feed their
data into other non-Raymarine instruments, the SeaTalk data needs to be translated into NMEA.
Even Raymarine's own navigation software, Raytech Navigator, needs this translation.
The multiplexer can be connected to a SeaTalk network. It will translate all SeaTalk data required
for navigation into NMEA sentences. NMEA In 4 can be switched to SeaTalk mode and should be
connected as follows:
Red
SeaTalk cable
Yellow
In 4A
In 4B
Multiplexer
Connecting a SeaTalk network
The screen of the SeaTalk cable is not connected to the multiplexer.
RS-232 Serial Port
The RS-232 serial port can be used to connect the multiplexer to a computer, as shown in the
diagram below. The serial port is bi-directional: the multiplexer sends NMEA data to the computer
and the computer can also send NMEA data back to the multiplexer. This data is available on
NMEA Out 1.
RxD
TxD
Com
2
3
Multiplexer
terminals
5
rear-view of
9-pin sub-D connector
The serial port is galvanically isolated from the multiplexer to prevent ground loops and excessive
currents that could otherwise destroy the multiplexer or the serial port of the connected computer.
The serial port is set to 38400 baud when shipped. It can however be set to any speed in the range
from 4800 to 38400 baud using the MPX-Config utility.
Power Supply
The multiplexer must be powered from an externally supplied DC voltage from 8 to 35V. The power
supply connection is protected against reversed polarity.
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Configuration
Various options can be configured on the multiplexer, using the configuration program MPXConfig that can be found on the accompanying CD. There is no installation procedure for this
utility, just start it from the CD or copy it to a suitable folder on the hard disk of your computer.
The top part of MPX-Config shows the NMEA sentences that are received by the multiplexer. The
bottom part shows the configuration controls.
The File menu allows you to store the configuration settings of the multiplexer to a file or load the
configuration from a file. This file format is similar to the Windows INI file format, allowing editing
the files with a text editor. See the Technical Reference section for an example of a configuration
file. Use the Log options from the File menu to store received NMEA sentences to a log file for
trouble-shooting purposes.
The multiplexer is configured with proprietary NMEA sentences. MPX-Config sends these
sentences to the multiplexer when you change an item on the screen but they can also be issued
with a terminal program. See the Technical Reference section for a complete reference of the
supported proprietary sentences.
All configuration settings are stored in the multiplexer’s non-volatile memory. These settings are
retained without power supply.
Screenshot of MPX-Config
Serial Port
Before being able to configure the multiplexer, select the serial port to which the multiplexer is
connected. When selecting the baud rate, either choose 38400 (factory default) of choose
Automatic to let MPX-Config detect the communication speed of the multiplexer automatically.
This may take a few seconds, especially when instruments are sending data to the multiplexer.
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When a ‘Multiplexer does not respond’ - message appears, disconnect or shut down the connected
instruments. Another way is to try every possible setting from 4800 to 38400 baud, until NMEA
data appears in the top window of MPX-Config when the Read Configuration button is pressed.
When the right baud rate has been found, the multiplexer will follow any change you make: when
you set the speed to 38400 baud, the multiplexer will also be set to this value in order to stay
‘synchronized’ with MPX-Config. If you exit MPX-Config, the settings will be saved.
NMEA Inputs/Outputs
This section allows you to set the speed of the NMEA inputs and outputs.
The settings range from 4800 to 38400 baud. Please note that In 4 and
Out 1 share the same speed setting. Out 1 is generally used to control
an autopilot and should be left at 4800 baud for this purpose. The same
goes for In 4, which should be left at 4800 baud when SeaTalk
translation is enabled.
Care should be taken when selecting other speeds than 4800 baud with
respect to possible buffer overflows. See paragraph ‘Overflow’ for more
information.
Read Configuration
Every time you start MPX-Config, it will retrieve the current configuration from the multiplexer.
When this is unsuccessful (various controls on the MPX-Config window stay greyed), you can
manually request the current configuration with this button.
The status line on the bottom of the MPX-Config window will show the name of the multiplexer,
the internal software version, the serial number and the optionally loaded configuration file.
Options
Various options can be enabled on the multiplexer by checking one of the
checkboxes shown on the right.
Priority
This option assigns a priority to incoming NMEA data, based on the input it
is received. The serial port input has the highest priority, followed by
NMEA In 1, In 2, In 3 and In 4 in descending order. If for instance two
GPS receivers are connected to input 1 and 2 and both GPS receivers
output GPRMC sentences, only those from the GPS on input 1 are passed.
This feature can be useful to set up a second GPS as a backup for the main GPS.
The multiplexer only uses the sentence formatter (the ‘RMC’ part) for comparison - the talker ID
(the ‘GP’ part) is ignored.
Another useful application of Priority is when a GPS and an AIS transponder are connected to the
multiplexer. An AIS transponder also outputs sentences from its internal GPS. A navigation
program now receives GPS data from two sources that might differ in position due to GPS
inaccuracy. This will lead to navigation errors. With the GPS connected to input 1 and the AIS
transponder to input 2, the NMEA data from the GPS is passed while similar NMEA sentences (e.g.
GPRMC) from the AIS transponder are blocked. When the GPS fails, a timeout mechanism ensures
that after 10 seconds the NMEA data from the AIS transponder is passed through the multiplexer.
Please note that the priority mechanism only blocks similar sentences. AIS sentences that are not
present on the GPS input are passed.
The following example shows what is passed and what not. The left column in the table shows
sentences from the GPS and the right column sentences from the AIS
transponder. The sentence that is greyed in the table is blocked by the
GPS
AIS
priority mechanism. The table shows that only the RMC sentence from
(In 1)
(In 2)
the AIS transponder is blocked.
GPRMC
GPRMC
The priority mechanism can store up to 50 sentence types to
GPGGA
AIVDM
determine their priority. A time-out on mechanism ensures that
sentence types on lower priority inputs are passed again when their counterparts on higher priority
inputs are no longer received.
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Channel Numbers
This option inserts channel number information in the NMEA stream that is output by the
multiplexer. Each NMEA sentence that is output on the serial port is preceded by the proprietary
NMEA sentence ‘$PSMDCN’ to indicate on which NMEA input the following sentence was received.
The following example shows that the IIGGA sentence was received on input 1, the GPGGA
sentence on input 2, the IIGLL sentence on input 1 and the HEHDT sentence on input 3.
$PSMDCN,1*1A
$IIGGA,143357.999,5301.0061,N,00635.5479,E,1,06,1.9,90.0,M,,,,0000*2E
$PSMDCN,2*19
$GPGGA,143357.999,5301.0061,N,00635.5479,E,1,06,1.9,90.0,M,,,,0000*39
$PSMDCN,1*1A
$IIGLL,5301.0061,N,00635.5479,E,143357.999,A*22
$PSMDCN,3*18
$HEHDT,67.0,T*1E
Channel numbers allow distinguishing between similar data from different instruments, like two
depth sounders on the same boat.
HDG -> HDT
This option converts an HDG sentence (magnetic heading) into an HDT sentence (true heading). If
the HDG sentence contains a magnetic variation, it is used to calculate the true heading from the
magnetic heading in the HDG sentence, otherwise the magnetic heading value is just copied. This
option can be used when a device like a Voyage Data Recorder needs a true heading from a
gyrocompass while only a fluxgate compass is available.
SeaTalk -> NMEA
To enable translation of SeaTalk® into NMEA, check this option. SeaTalk is a proprietary protocol
developed by Raymarine® and it is used for communication between Raymarine navigation
instruments like the ST40, ST50 and ST60 series. To be able to use these instruments with
commonly available navigation programs or to feed their data into non-Raymarine instruments, the
SeaTalk data needs to be translated into NMEA. See the Technical Reference section for an
overview of the SeaTalk data that is translated into NMEA.
AIS on In 1
This option enables AIS mode for input 1, to be able to connect an AIS receiver or transponder to
the multiplexer. It sets the speed of In 1 to 38400 baud and it prevents data received on In 1 to
be sent to Out 1 when the multiplexer is in Hub or Auto mode.
It is very well possible to connect an AIS receiver or transponder to any input and set that input to
38400 baud, but this requires the multiplexer to be set to Server mode to prevent the AIS data
from being sent to Out 1, the port that is generally used to control an autopilot at 4800 baud.
Mode of Operation
The multiplexer can operate in three different modes: Server, Hub and
Auto Hub/Server. Basically, these modes determine which NMEA data
is available on NMEA Out 1.
Server mode:
In this mode, the combination of computer and
multiplexer acts as an NMEA server. Incoming NMEA
data from NMEA In 1 to In 4 is sent to the computer
and NMEA Out 2. NMEA Out 1 only outputs data received from the computer.
Hub mode:
In Hub mode, the multiplexer acts as a hub where all NMEA data comes together
and is sent out again. All incoming NMEA data from NMEA In 1 to In 4 and the
computer is available on NMEA Out 1.
This mode has one limitation: since the NMEA data is sent to multiple outputs on
the multiplexer, the total throughput is limited by the speed of the slowest output.
This may cause buffer overflows.
Auto mode:
When Auto Hub/Server mode is selected, the multiplexer automatically switches
between Hub and Server mode, depending on the presence of computer
generated data. When the multiplexer receives NMEA data from the computer, it
switches to Server mode. When no data is received from the computer for more
than 10 seconds, the multiplexer will switch to Hub mode.
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Auto mode is very useful when sailing alternately with our without a laptop. Consider a typical setup as shown below:
Wind
In 1
Laptop
RS-232
Compass
In 2
GPS
In 3
Out 1
Multiplexer
Auto-pilot
When the laptop is connected, it will receive all information from the instruments and the running
navigation software is able to calculate the course to steer and drive the autopilot accordingly.
Because the laptop is sending NMEA data, the multiplexer operates in Server mode and the
autopilot on NMEA Out 1 will therefore receive information from the laptop only.
When the laptop is not connected or the navigation software is not sending any data, the
multiplexer switches to Hub mode and sends all data from the instruments directly to the
autopilot. This way, the autopilot will receive course information directly from the GPS.
NMEA Out 2 is not affected by the mode setting. On this output, only NMEA data from the NMEA
inputs is available.
Real-Time
The Real-Time option bypasses the buffer on a specific channel. In normal
operation, all incoming NMEA sentences are stored in a buffer, one for each channel,
which hold several seconds of NMEA data. In situations with heavy NMEA traffic,
these buffers can be filled up quite rapidly until an overflow occurs (red LED blinks).
Normally an overflow situation does not pose an immediate problem, it only means
that every now and then an incoming NMEA sentence is discarded because there is
no room left in the buffer.
However, when a fluxgate or gyrocompass is connected, which sends it’s heading 10 or 20 times
per second, the corresponding input buffer on the multiplexer is filled up constantly. Together with
NMEA data from other instruments, the total amount of data passing through the multiplexer gets
so high that almost all used inputs are in constant overflow, resulting in an unacceptable delay of
information of up to 20 seconds. This makes it impossible for an autopilot to steer on a compass
heading.
By enabling the Real-Time option on the channel that is connected to the gyro or fluxgate
compass, the buffer on that channel is bypassed and the NMEA data from the compass is passed
through the multiplexer without delay. Some NMEA sentences will be discarded when
the multiplexer is servicing another channel but this is far less of a problem than
having a 20 second delay in the heading information.
The overflow indicators on the MPX-Config screen can also be used to determine
which channel is causing the overflow. The LED corresponding to the compass
channel will be lit almost continuously. See the section ‘Overflow’ for ways to prevent
overflow situations.
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Talker ID
The multiplexer allows you to change the talker ID of incoming sentences, the
first two characters of an NMEA sentence that determine which instrument
(talker) the sentence is originating from. Enter the desired talker ID in the edit
box of the desired channel and press the Set button to send the setting to the
multiplexer. Pressing the Read Configuration button will read the Talker ID
settings from the multiplexer. To clear a talker ID, simply clear the edit box(es)
and press the Set button. Please note that any combination of two characters can
be used as talker ID, including spaces. Therefore, make sure you clear the edit
box and not fill it with spaces if you want to clear a talker ID.
With the setting as shown on the right, any NMEA sentence received on input 1
will get talker ID ‘II’. Thus a GPRMC sentence from a GPS will be changed into IIRMC.
This feature can be useful when similar sensors are connected to the multiplexer and the software
must be able to distinguish between the data from these sensors. A catamaran for instance could
have a depth sensor in each hull, sending similar sentences to the navigation software.
Sentence Filter
The sentence filter is a powerful feature that allows you to specify exactly which NMEA sentence
may be received on any channel, including the serial port. Up to 50 rules can be entered, either
manually or by capturing the NMEA sentences received by the multiplexer.
Each filter rule consists of the address field of an NMEA sentence (2 characters for the talker ID
and 3 characters for the sentence formatter like ‘GPRMC’) and an indicator for each channel (Inputs
1 to 4 and the PC). Wildcards are allowed in the sentence formatter by using the ‘-’ character. The
indicator can be toggled between a pass sign ( ) and a block sign ( ) by clicking on it. This
determines whether that specific sentence will be passed or blocked by the multiplexer.
Whenever the multiplexer receives an NMEA sentence, the filter list is traversed until a match is
found. The order of filter entries is exactly the same as shown in MPX-Config. When a match is
found, the input on which the sentence was received is checked against the input settings in this
rule to determine whether the sentence may be passed or not.
When no match is found, the received sentence is passed. This means that all sentences for which
no rule exist, are passed through the multiplexer.
Example 1
The first step is to fill the list with NMEA sentences to be
filtered. This can be done automatically by pressing the
Capture button. All controls will be disabled during
capture and the Capture button changes to Stop.
Leave the capture mode running for approximately 10
seconds. By that time, all connected instruments will
have sent NMEA sentences. Press Stop to end the
capture mode.
To make sure all sentences are captured properly, no
Talker ID’s may be set for the input channels.
After the capture process, the list may look like the
example on the right: the list shows received sentences
GLL and RMC on input 1 and HEHDT on input 2 (GLL and
RMC would have been preceded by GP but more on that later).
If for instance the GGA and GLL sentences have to be blocked, simply click on the pass signs of
both sentences to change them into a block sign. Pressing the Store button sends the list to the
multiplexer. Now the filter is operational. Please note that the multiplexer will suspend its operation
for a few seconds while storing the list in non-volatile memory.
As can be seen in the picture, the GLL and RMC sentences contain two dashes (‘--’) to indicate a
wildcard. This means that the first two characters are not used in the comparison with received
data. In this case, the filter processes anything that has a sentence formatter of GLL or RMC. When
a list is captured, you can click on a sentence with the cursor and edit the characters of that list
entry. Thus a captured sequence with ‘GPRMC’ and ‘GPGLL’ can be changed into ‘--RMC’ and
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‘--GLL’. A useful purpose for wildcards is to block proprietary sentences from a device by entering
‘P----’ in the filter list. This will block any sentence that starts with a ‘P’.
The optional number in the last column is a divisor factor. By default, this number is 0, which
means that every occurrence of that sentence is passed. To lower the frequency of a sentence, a
number between 2 and 99 can be entered. For instance, if a fluxgate compass is sending 10
sentences per second, and the multiplexer or a connected device is suffering from an overflow, you
can enter a 5 in the divisor column. The effect is that every fifth sentence will be passed while all
others are blocked. This brings the sentence frequency down from 10 to 2 sentences per second.
Example 2
As mentioned before, all sentences are passed for which
no rule exists. It can be desired however to reverse this
operation: when no rule exists, a sentence is blocked on
all inputs. This behaviour can be achieved by adding an
all wildcard entry to the end of the list with all inputs
blocked. This entry acts as a ‘catch-all’ rule. When no
match is found in the list, this last rule will always match
a sentence and causes it to be blocked. The picture shows
such a list.
Managing the list
The filter list is managed in MPX-Config and can be
stored to or retrieved from the multiplexer. Clicking on a
traffic sign toggles it between a pass sign ( ) and a block
sign ( ), which determines whether that specific sentence
will be passed or blocked on that input. Each column
represents an input of the multiplexer, including the input from the computer (PC). The following
management functions are available:
Store
Stores the filter list from MPX-Config in the multiplexer. Any existing filter rules in the
multiplexer are overwritten with the ones in the list. Note that the multiplexer will
suspend its operation for a few seconds while storing the list in non-volatile memory.
Load
Loads the filter list from the multiplexer into MPX-Config. The loaded filter rules are
added to any existing rules in the list. If you do not want this, clear the list by pressing
the Clear List button first.
Delete
Delete a filter rule from the list in MPX-Config. Select the filter rule to be deleted by
clicking on the formatter (e.g. ‘RMC’) and press the Delete button.
Capture
Enables capture mode. The filter list will be filled automatically with the NMEA
sentences that are received by the multiplexer. For this function to work properly, it is
necessary that any Talker ID settings be cleared first. Otherwise, the list will be filled
with modified sentences instead of the originals.
Add
Add a filter rule. Type the desired sentence address into the edit box above the Add
button and press Add or the enter key. This will enter a new filter rule with all channels
blocked ( ). The input is case-insensitive; every entered sentence formatter will be
converted into uppercase. The input must contain 5 characters, including wildcards.
Clear List This button clears the filter list in MPX-Config (not the multiplexer!). To clear the list
in the multiplexer, press the Store button after clearing the list in MPX-Config.
Manual NMEA input
MPX-Config allows manual entry of NMEA
sentences for testing, configuration etc.
Type the desired NMEA sentence in the edit box
as shown on the right and press the Send
button or the enter key. Preceding the NMEA
sentence with a ‘$’ is optional. MPX-Config will
add a ‘$’ if necessary. The input is case sensitive, so whatever you type will be sent literally to the
multiplexer. Since all NMEA commands are uppercase, you have to enter them as uppercase.
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Indicators
The multiplexer has two LED’s. The green LED indicates the reception of valid NMEA data on the
listener ports or the serial port. The LED only blinks on valid NMEA sentences that start with a ‘$’ or
‘!’ and end with a CR and LF character, thus indicating a proper connection and polarity of the
connected instrument. In case of a reverse polarity, the green LED will not blink.
The red LED indicates a buffer overflow, in case more data is coming in than can be transmitted.
See section ‘Overflow’ for options to resolve this situation.
Mounting
The multiplexer is not waterproof. It should be mounted at a dry place, like behind the instrument
panel, on a flat surface.
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Technical Reference
MPX-Config Registry keys
The serial port settings of MPX-Config are stored in the Windows registry, using the following
keys:
HKEY_CURRENT_USER\Software\CustomWare\MPXConfig\BaudRate
HKEY_CURRENT_USER\Software\CustomWare\MPXConfig\SerialPort
MPX-Config INI file format
The configuration file format of MPX-Config resembles the standard Windows INI file format and is
readable text.. Below is an example with has all possible options listed. The example corresponds
with the settings shown on the MPX-Config screenshot on page 6.
[Configuration]
Priority=0
Channel Numbers=0
HDG Translation=0
AIS Mode=0
SeaTalk=1
Mode=0
RealTime Ch.1=0
RealTime Ch.2=0
RealTime Ch.3=0
RealTime Ch.4=0
Talker ID1=II
Talker ID2=
Talker ID3=WI
Talker ID4=
Baud In1=0
Baud In2=0
Baud In3=0
Baud In4/Out1=0
Baud Out2=3
[Filter]
GPRMC=01000,0
HCHDT=00100,5
IIMWV=00010,0
IIMTW=00010,0
--GLL=00000,0
--GGA=00000,0
--GSV=00000,0
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Proprietary NMEA commands
The multiplexer supports some NMEA commands through proprietary NMEA sentences. They also
generate certain proprietary NMEA sentences in some modes of operation or as a response to
NMEA commands.
All commands have the following format:
$PSMDxx
$P:
SMD:
xx:
Start of a proprietary command. Dictated by the NMEA standard.
ShipModul manufacturer’s mnemonic.
Two- or three-character command code.
For ease of manual configuration, the commands issued to the multiplexer do not require a
checksum. Sentences output by the multiplexer always contain a checksum. Sentences output by
the multiplexer always contain a checksum denoted with ‘*hh’ in the descriptions below.
Command reference
VER – Get Version
Retrieves version information from the multiplexer. The multiplexer responds with the following
version sentence:
$PSMDVER,2.10,MiniPlex-2S,10025943,8000*hh<CR><LF>
2.10:
MiniPlex-2S:
10025943:
8000:
software version number
product descriptor
serial number
multiplexer capabilities. This is a 4 digit, 16-bit field represented as a
hexadecimal number. Each bit identifies a capability of the multiplexer. The
following bits are defined:
2-0: Interface type, 0 = serial, 1 = USB, 2 = Bluetooth
15: 3rd generation multiplexer
hh:
checksum
CN - Channel Number indicator
This sentence precedes an NMEA sentence to indicate through which input channel the sentence
was received.
$PSMDCN,x*hh<CR><LF>
x:
hh:
channel number 1,2,3 or 4.
checksum
Example: $PSMDCN,1*1A<CR><LF>
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CF – Configuration
This sentence sets the configuration of the multiplexer. The same sentence is sent by the
multiplexer in response to a CFQ sentence.
Command: $PSMDCF,b,m,s,p,n,rrrr,h,a[*hh]<CR><LF>
b: baudrate selector:
m: mode selector:
0
1
2
3
9
=
=
=
=
=
4800 baud
9600 baud
19200 baud
38400 baud
toggle checksum mode
1)
0 = Server mode
1 = Hub mode
2 = Auto mode
s: Seatalk translation: 0
1
2
3
4
=
=
=
=
=
off
on
dump all unknown Seatalk datagrams (PSMDST,xx,xx,…)
dump all Seatalk datagrams
toggle generated wind sentence between VWR and MWV
p: Channel priority:
1 = on, 0 = off
n: Channel numbers:
1 = on, 0 = off
r: Real-time mode:
1 = on, 0 = off. Four digits, one digit per channel, numbered from 1 to 4
h: Heading translation: 1 = on, 0 = off
a: AIS mode:
1 = on, 0 = off
hh: optional checksum
When sending this command to the multiplexer, it is not necessary to specify every field when only
one configuration parameter has to be changed. Fields preceding the one to be changed can be left
blank. Fields after the one to be changed may be omitted. When for example only the channel
priority must be changed, the command ‘$PSMDCF,,,,1’ may be sent. The fields ‘b’, ‘m’ and ‘s’ are
left blank while the fields for ‘n’ and ‘rrrr’ are omitted.
The ‘s’ field will always return a 0 or 1 in response to a CFQ command.
1) Normally the multiplexer blocks sentences that contain a checksum error. Toggling the
checksum mode lets the multiplexer pass sentences with a checksum error unprocessed. The
response of the CFQ command shows in which mode the multiplexer is configured: when a
checksum is added, the multiplexer is in normal mode and blocks erroneous sentences. When
the CF response shows no checksum, the multiplexer passes erroneous sentences.
CFQ – Request current configuration
This sentence requests the current configuration settings from the multiplexer.
$PSMDCFQ<CR><LF>
The multiplexer responds with a CF sentence. When the response contains a checksum, the
multiplexer is in normal mode and blocks erroneous sentences. When the CF response shows no
checksum, the multiplexer passes erroneous sentences.
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SP – Speed
This sentence sets the baud rate of the NMEA inputs and outputs.
$PSMDSP,a,b,c,d,e[*hh]<CR><LF>
The following fields are defined for setting the various ports:
a:
b:
c:
d:
e:
NMEA
NMEA
NMEA
NMEA
NMEA
In 1
In 2
In 3
In 4/Out 1
Out 2
Each field accepts the following value:
0
1
2
3
=
=
=
=
4800 baud
9600 baud
19200 baud
38400 baud
SPQ – Request Speed
Request the baud rate settings of the NMEA inputs and outputs.
$PSMDSPQ<CR><LF>
The multiplexer responds with a $PSDMSP sentence.
FL – Filter
This sentence specifies a filter rule which is applied on every incoming NMEA sentence. Sentences
for which a rule is specified, will only be transferred if the input on which they are received
matches the input specified in the filter rule.
Filter rules are specified by the formatter part of the NMEA address field, for instance the ‘GPRMC’
part of a GPS ‘$GPRMC’ sentence. For each filter rule, the inputs to be passed can be specified.
Sentences for which no rule exists are passed unrestricted.
$PSMDFL,ccccc,xxxxx,[dd][*hh]<CR><LF>
ccccc:
Sentence formatter of the filter rule (e.g. ‘GPRMC’, ‘IIMWV’, etc). This field may contain
wildcard characters (‘-’). For instance, ‘GP---’ will apply to all sentences starting with
‘GP’. Similarly, ‘--MWV’ will apply to all sentences ending on ‘MWV’ regardless of the
talker ID. One filter rule with all wildcards and all inputs blocked is allowed to let the
multiplexer block all sentences for which no rule exists. When an all-wildcard rule is
entered, the multiplexer will not accept subsequent filter rules.
Example: $PSMDFL,-----,00000<CR><LF>
xxxxx:
Inputs to pass. Each ‘x’ represents an input to assign to this rule, numbered from 0 to
4, where input 0 is the computer interface and 1 to 4 represent NMEA inputs 1 to 4. A
‘1’ means to pass, a ‘0’ means to block. When all x’es are ‘1’, the filter rule is removed.
dd:
Optional divisor factor (0..99). The frequency of a sentence is divided by this number
to reduce the number of sentences over time. If for instance a divisor of 6 is specified
for a sentence, only every 6th sentence is passed. This can be used to reduce the
output of a high-speed heading sensor.
hh:
Optional checksum
A FL sentence without any parameters will erase all rules.
Example: $PSMDFL,GPRMC,10011<CR><LF>
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This sentence specifies a rule for all sentences that have the ‘GPRMC’ sentence formatter. When
this rule is applied, only ‘GPRMC’ sentences on inputs 0 (the computer), 3 and 4 are passed.
FLQ – Request filter list
This sentence requests the filter list from the multiplexer. The multiplexer responds by sending FL
sentences, one for each list entry. An empty FL sentence denotes the end of the list.
Example:
$PSMDFL,GPRMC,10011,0*hh<CR><LF>
$PSMDFL,GPGGA,10001,0*hh<CR><LF>
$PSMDFL,--VWT,01000,5*hh<CR><LF>
$PSMDFL,GPGSV,00001*hh<CR><LF>
$PSMDFL,*hh<CR><LF>
The sentences may not be dumped as one contiguous block. In case of heavy NMEA traffic, they
may be interspersed with other NMEA sentences.
ID – Talker ID
Enables a Talker ID to be set for a specific channel. If the talker ID is set for a specific channel, the
original talker ID in the sentences received on that channel is replaced by the specified one before
sending the sentence to the computer.
$PSMDID,aa,bb,cc,dd[*hh]<CR><LF>
aa:
bb:
cc:
dd:
hh:
Talker ID for channel
Talker ID for channel
Talker ID for channel
Talker ID for channel
optional checksum
1
2
3
4
An empty field clears the ID and disables the translation for that specific channel. Sending a
PSMDID sentence without any fields clears all ID’s.
IDQ – Request talker ID’s
Requests the Talker ID settings. The multiplexer responds with an ID sentence.
OV – Overflow
In case of a buffer overflow (blinking red LED on the multiplexer), an overflow sentence is output,
to indicate on which input buffer the overflow occurred:
$PSMDOV,x<CR><LF>
x:
Binary field. The first four bits indicate on which input buffer the overflow occurred.
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Translated Seatalk datagrams
When the Seatalk translation is enabled, the following datagrams are translated into NMEA
sentences:
SeaTalk
00
10
11
20
21
22
23
25
26
27
50
51
52
53
NMEA
DBT
MWV
MWV
VHW
VLW
VLW
MTW
VLW
VHW
MTW
------RMC
54
56
58
84
89
99
9C
------HDG
HDG
--HDG
Description
Depth below transducer
Wind angle, (10 and 11 combined)
Wind speed, (10 and 11 combined)
Speed through water
Trip mileage (21 and 22 combined)
Total mileage (21 and 22 combined)
Water temperature
Total and Trip mileage
Speed through water
Water temperature
Latitude, value stored
Longitude, value stored
Speed over ground, value stored
Course over ground. RMC sentence is
generated from stored values from 5x
datagrams.
GMT time, value stored
Date, value stored
Lat/Long, values stored
Magnetic heading, including variation (99)
Magnetic heading, including variation (99)
Magnetic variation, value stored
Magnetic heading, including variation (99)
As appears from the table, not all datagrams result in an NMEA sentence. Some datagrams are
only used to retrieve a certain value to be combined into one NMEA sentence.
When the Seatalk translation is enabled with with option 2 (the ‘s’ parameter in the CF sentence is
2), unlisted datagrams are translated into a proprietary NMEA sentence with the following format:
$PSMDST,aa,bb,cc,dd…*hh<CR><LF>
aa,bb,cc,dd… represent the hexadecimal value of the bytes from the received Seatalk datagram.
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Technical Specifications
Supply voltage:
8 – 35 VDC, protected against reversed polarity.
Current consumption:
50 mA (100 mA max. with fully loaded talker ports).
Inputs:
4 x NMEA-183/RS-422, galvanically isolated. Input 4 can be set
to SeaTalk mode.
Input resistance:
>800 Ohm.
Outputs:
1 x RS-232, galvanically isolated.
2 x NMEA-183/RS-422.
Buffers:
5 buffers of 800 characters (4 x NMEA, 1 x RS-232).
Filter list size:
50 sentence types
Priority list size:
50 sentence types
NMEA Out 1:
Combined data from NMEA inputs and serial port (Hub mode) or
from serial port only (Server mode).
NMEA Out 2:
Combined data from NMEA inputs.
Speed NMEA In 1-3:
4800 - 38400 baud.
Speed NMEA In 4/Out 1:
4800 - 38400 baud.
Speed NMEA Out 2:
4800 - 38400 baud.
Speed serial port:
4800 - 38400 baud.
Indicators:
Overflow and Data.
Dimensions:
138 x 72 x 33 mm.
Housing:
Flame retardant ABS.
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Declaration of Conformity
We,
CustomWare
Borgstee 27b
9403 TS Assen
The Netherlands
Tel.: +31 592 375700
Fax: +31 592 375550
Declare under our sole responsibility that the product
ShipModul MiniPlex-2S
to which this declaration relates is in conformity with the following specifications:
EN/IEC60945:2002 and EN/IEC61162-1:2000
FCC Title 47 CFR, Part 15 Class B
The product herewith complies with the requirements of the EMC Directive 89/336/EEC and carries
the CE-marking accordingly.
Assen, 1-7-2010
M. Sprang
This device complies with Part 15 of the FCC Rules. Operation is subject to the following conditions:
(1) This device may not cause harmful interference, and (2) this device must accept any
interference received, including interference that may cause undesired operation.
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ShipModul / CustomWare
Borgstee 27b
9403 TS Assen
The Netherlands
Tel.:
Fax:
+31 592 375700
+31 592 375550
web: www.shipmodul.com
e-mail: [email protected]
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